Rotavirus

CDC/Dr. Erskine Palmer
Transmission electron micrograph of intact rotavirus particles
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Rotavirus is the most common cause of severe diarrhea in children and infants worldwide. Before a vaccine was introduced in the United States, the disease caused more than 400,000 doctor visits and 200,000 emergency room visits each year, resulting in as many as 60 deaths annually in children younger than five. Globally, rotavirus kills more than 500,000 children each year, with most deaths occurring in developing countries.

Symptoms and Causative Agent

Rotavirus is a double-stranded RNA virus of the reovirus family. Viewed under an electron microscope, the virus is shaped like a wheel, hence its name (rota being Latin for “wheel”). Several species and subtypes of rotavirus cause disease in humans.

The most common symptom of rotavirus infection is watery diarrhea. It may also cause fever, abdominal pain, and vomiting. Complications from rotavirus infection are described below.

Transmission

Rotavirus spreads via the fecal-oral route -- that is, from the waste of an infected person to the mouth of another individual. This can occur via contamination on hands or objects such as toys. The virus spreads easily among children and can also be passed from children to those with whom they are in close contact.

A person’s first infection with rotavirus usually causes acute illness, but later infections produce milder symptoms and are often asymptomatic (meaning they cause no visible symptoms). Asymptomatic infections in adults, however, may lead to transmission of the virus to close contacts.

Treatment and Care

No specific treatments exist for rotavirus infections. Rather, they are treated with supportive care, such as oral rehydration, rest, and fever relief.

Complications and Mortality Rate

In about 1 in 50 cases of rotavirus illness, children develop severe dehydration from diarrhea and vomiting. Hospitalization is usually necessary in these cases, and children are rehydrated via liquids delivered via nasogastric tube or intravenously. Prompt rehydration therapy usually leads to a positive outcome, but deaths from rotavirus still do occur in developed countries and, more commonly, developing countries.

Available Vaccines and Vaccination Campaigns

The first vaccine for rotavirus, RotaShield, was licensed and recommended for routine childhood immunization in 1998. Wyeth Pharmaceuticals, however, withdrew the vaccine in 1999 due to safety concerns. Scientists associated the vaccine with a rare intestinal problem called intussusception, a potentially fatal telescoping of part of the bowel.

No rotavirus vaccine was available until 2006, when the Advisory Committee on Immunization Practices recommended routine infant immunization with three doses of the recently licensed RotaTeq vaccine, developed by H. Fred Clark, PhD, Stanley A. Plotkin, MD, and Paul A. Offit, MD. The Food and Drug Administration licensed another rotavirus vaccine, Rotarix, for use in the United States in 2008. Rotarix is given to infants in two doses.

CDC has carefully monitored incidence of rotavirus disease in the United States since 2000. Their studies show that that the number of positive test results for rotavirus was substantially lower than the median observed during 2000-2006. Additionally, it appears that hospitalization rates for acute gastroenteritis dropped by 16% in 2007 and by 45% in 2008 compared with the earlier period. Researchers have estimated that rotavirus vaccination prevented about 55,000 hospitalizations in 2008.

Worldwide, rotavirus continues to take a toll. More than 500,000 children under age 5 die each year from rotavirus illness. Efforts are being made to make rotavirus vaccine available throughout the developing world, where deaths from rotavirus illness are more common. Mexico was one of the first countries to receive rotavirus vaccine in 2006; by the 2009 rotavirus season, death rates from diarrheal disease had dropped in both the target population for vaccination (children younger than 11 months old, where the rate dropped by 40%) and among children between one and two years of age (by almost 30%). The fact that death rates dropped even in a part of the population that is not targeted by the vaccine suggests that herd immunity benefited the unvaccinated individuals: with fewer infections to begin with, the disease circulated less in the population, leaving less opportunity for exposure.

Following are the general recommendation for rotavirus vaccination in the United States:

Rotavirus vaccination is recommended for all children, starting at two months of age in a two- or three-dose series spread over many weeks, to be completed by the time the infant is four months old (for the two-dose series) or six months old (for the three-dose series).


Sources

Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. Rotavirus. Atkinson W, Wolfe S, Hamborsky J, eds. 12th ed. Washington DC: Public Health Foundation, 2011. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/rota.pdf (562 KB). Accessed 2/10/2014.

Feigin RD, Cherry JD, Demmler GJ, Kaplan SL. Texbook of Pediatric Infectious Diseases, 5th ed., vol 2. Philadelphia: Saunders, 2004.

Plotkin SA, Orenstein WA, Offit PA. Vaccines, 5th ed. Philadelphia: Saunders, 2008.

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Last update 10 Feb 2014

Timeline Entry: 5/14/2010 Rotavirus: FDA Supports Vaccine

After several weeks of developing news about a pig virus and pig viral DNA in rotavirus vaccines, the U.S. Food and Drug Administration announced that the two U.S. licensed rotavirus vaccines should continue to be used.

Scientists using a newly developed tool had discovered a pig virus in GlaxoSmithKline’s Rotarix in March 2010, prompting the FDA to suspend its use.

Further studies showed pig virus fragments in Merck’s RotaTeq vaccine.

The pig viruses do not infect humans and were almost certainly present in the vaccines during their initial clinical tests and licensure. (They were derived from one of the chemicals used to prepare the cells in which the rotavirus vaccine strains are grown.) No adverse events have been associated with the pig viral materials in the vaccines.

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